69 STILL doesn't run right
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Joined: Nov 2006
Posts: 51
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From: New York
69 STILL doesn't run right
Thanks to all who have contributed info to my problem, but it didn't go away!! To review:
I have changed Plugs,wires, cap, rotor, points, coil.
I have set the dwell, timing, adjusted all my valves,
cleaned out my carburetor, checked for vacuum leaks, looked for misaligned belts,and checked the fan for wobble. The car does not smoke, burn oil, or overheat. It starts right up hot or cold.
It is a stock 1969 vette 350 cu/ 350 hp motor, no A/C convertible.
The problem is it has a vibration all through the RPM range. It seems to me like some kind of miss (not using all cylinders??). It never goes away!! I know it could be a major engine problem but it doesn't seem that bad. Could the distributor be off by maybe one gear and the car still run? Thats my next guess. Any other ideas? Thanks again for your help.
I have changed Plugs,wires, cap, rotor, points, coil.
I have set the dwell, timing, adjusted all my valves,
cleaned out my carburetor, checked for vacuum leaks, looked for misaligned belts,and checked the fan for wobble. The car does not smoke, burn oil, or overheat. It starts right up hot or cold.
It is a stock 1969 vette 350 cu/ 350 hp motor, no A/C convertible.
The problem is it has a vibration all through the RPM range. It seems to me like some kind of miss (not using all cylinders??). It never goes away!! I know it could be a major engine problem but it doesn't seem that bad. Could the distributor be off by maybe one gear and the car still run? Thats my next guess. Any other ideas? Thanks again for your help.
Last edited by US300hp; Jun 14, 2007 at 05:07 PM.
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From: New York
Team Owner
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From: Columbia Missouri
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Joined: Nov 2006
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From: New York
Good question!! Basically I was moving the distributor back and forth to see if it would affect the vibration. Whether I was advancing or retarding the timing it didn't seem to make a difference. The engine reacted the way you would expect but the infamous miss/vibration did not get affected.
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Drifting
Joined: Sep 2004
Posts: 1,959
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From: North Bend Ohio
Which cylinder is missing? If you don't know which one it is start pulling plug wires one at a time until you get one that doesn't drop the idle RPM. You may be able to at least zero in on one cylinder this way. If you do find that it is one cylinder pull the valve cover to make sure the valve train is still functioning.
This could be a flat cam lobe, pulled through rocker arm, bent pusher rod, pulled rocker stud, broken valve spring or sticking lifter.
BigBlockk
Later.....
This could be a flat cam lobe, pulled through rocker arm, bent pusher rod, pulled rocker stud, broken valve spring or sticking lifter.
BigBlockk
Later.....
Race Director
Joined: Sep 2004
Posts: 11,874
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
no the distributor is not off one tooth, your timing would correct for that......however if the timing chain jumped......you did verify the firing order and that all plug wires are where they should be?
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From: New York
Thread Starter
Advanced
Joined: Nov 2006
Posts: 51
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From: New York
Which cylinder is missing? If you don't know which one it is start pulling plug wires one at a time until you get one that doesn't drop the idle RPM. You may be able to at least zero in on one cylinder this way. If you do find that it is one cylinder pull the valve cover to make sure the valve train is still functioning.
This could be a flat cam lobe, pulled through rocker arm, bent pusher rod, pulled rocker stud, broken valve spring or sticking lifter.
BigBlockk
Later.....
This could be a flat cam lobe, pulled through rocker arm, bent pusher rod, pulled rocker stud, broken valve spring or sticking lifter.
BigBlockk
Later.....
Pro
Joined: Jul 1999
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From: smithfield nc usa 27577
Lets see, bad plug,bad wire,vac advance on dist not conected,points not gapped right,timing set wrong,vacum leaks,bad motor mount....
Look to make sure you got all your vac lines on the carb right,and the dist. vac connected.
Did you time it with the vac advance connected or disconnected?
Incorrect plug gap or points gap..?
trash in carb..
The trick with these tune ups is to fire the car after each job.
If the car starts running like crap then you know what it was you just did.I have been though this many times. Just start looking at each area and cross them off one at a time.Dont mess with new things if you can help it, the more things you mess with the longer the list of maybe s become. Good luck.
If you are unsure what to do next just pm me I can shoot you a phone # maybe I can help.
Look to make sure you got all your vac lines on the carb right,and the dist. vac connected.
Did you time it with the vac advance connected or disconnected?
Incorrect plug gap or points gap..?
trash in carb..
The trick with these tune ups is to fire the car after each job.
If the car starts running like crap then you know what it was you just did.I have been though this many times. Just start looking at each area and cross them off one at a time.Dont mess with new things if you can help it, the more things you mess with the longer the list of maybe s become. Good luck.
If you are unsure what to do next just pm me I can shoot you a phone # maybe I can help.